Tools for plugging in and unplugging subsystems carried on slideways

ABSTRACT

A portable tool permitting, as desired, either selective plugging in of a printed-circuit module into one of a plurality of bottom grooves formed in a rack and above which groove the module is restrained by lateral slideways, or selective unplugging of one of the modules plugged into the bottom rack grooves. It comprises a grip formed by two elements movable relatively to each other. One of these elements is provided with a pair of claws adapted to engage lateral recesses in the rack when the operator moves the two grip elements toward each other. The other element is provided on the one hand, with pushing rods acting on the module to be plugged and, on the other hand, with hooks acting on the module to be unplugged, after having turned the grip the other way round.

United States Patent Baillard 1151 3,696,492 1451 Oct. 10, 1972 [72]Inventor: Marcel Baillard, Seine, France [73] Assignee: SocieteNationale Industrielle Aerospatiale, Paris, France [22] Filed: March 9,1971 [21] Appl. No.: 122,389

[30] Foreign Application Priority Data March 18, 1970 France ..700975252 us. c1. ..29/203 11 511 1111.01. ..B25b 27/02 58 Field ofSearch...29/203 H, 203 B, 278; 294/15, 294/16, 28

[56] References Cited UNITED STATES PATENTS 3,443,297 5/1969 Lusby..29/203 H 11/1970 Bruner ..29/203 H 12/1971 Greenspan ..29/203 11Primary Examiner-Robert C. Riordon Assistant Examiner-J. C. PetersAttorney-Karl W. Flocks [5 7] ABSTRACT A portable tool permitting, asdesired, either selective plugging in of a printed-circuit module intoone of a plurality of bottom grooves formed in a rack and above whichgroove the module is restrained by lateral slideways, or selectiveunplugging of one of the modules plugged into the bottom rack grooves.It comprises a grip formed by two elements movable relatively to eachother. One of these elements is provided with a pair of claws adapted toengage lateral recesses in the rack when the operator moves the two gripelements toward each other. The other element is provided on the onehand, with pushing rods acting on the module to be plugged and, on theother hand, with hooks acting on the module to be unplugged, afterhaving turned the grip the other way round.

5 Claims, 9 Drawing Figures PATENTEDnm 10 m2 SHEET 1 0F 7 INVENTORMARCEL BAILLARD BY Kan L Ffocn H TTOR/VE Y The use of equipment fortesting or controlling the electro-mechanical circuits to be found insystems of all kinds employed in the various spheres of modern activityhas resulted in the introduction of cabinets of by no means negligiblesize, equipped with slide-in units or racks containing the equipmentdesigned to perform the required functions.

In order, on the one hand, to reduce the number and size of suchindividual items and hence the cost of each installation and, on theother, to simplify the equipment handling operations inherent in theperformance of each operation, it has been necessary to devise modulescorresponding to specific circuits. These modules, which are made ofinsulating material, carry printed circuits and provide the requisiteelectronic components, are removably and interchangeably inserted intoslideway systems with which the above-mentioned racks are equipped and,by their very association, provide the circuits needed for performingthe required operation.

Experience has shown that notwithstanding these slideways the insertionor withdrawal of each such module, into and from the various racks,represents a very delicate manual operation by reason of the very smallgaps existing between consecutive modules, which gap must nonethelesspermit insertion or withdrawal of each module in addition toaccommodating the various components equipping the printed circuits andwhich bulk to a considerable extent due to the presence of transistors,capacitors, resistors and so forth.

In view of these difficulties and in order to avoid damage to themodules, their circuits and their equipment as the result of inadvertentclumsiness when inserting or withdrawing the modules, the need arose todesign and develop a device for plugging in or unpiugging these modules.

During insertion, each module is introduced manually along the siderails provided in the rack. On the other hand, the final operation-ofplugging in, i.e., of engaging it into the bottom groove, is muchtrickier because it involves exerting a considerable force uniformlydistributed over the upper edge of the module in order to ensure correctengagement. This delicate operation can be accomplished in outstandinglysimple, efficient and reliable fashion by means of the devicespecifically designed for the purpose and which forms the object of thepresent invention.

This device is designed to make it possible to perform the reverseoperation of selectively withdrawing modules one by one. Previously,this unplugging operation also required the application of a force, thistime in the opposite direction, and which, again in order to avoiddamaging the equipment, is uniformly distributed over the entireperiphery of the module and is directed rigorously along the plane ofsymmetry of withdrawal of each module.

In other words the present invention relates to a simple, easy to handledevice, requiring no special precautions in use, which, by being merelyapplied against the rack level with the corresponding rails, makes itpossible to plug in or unplug the required modules by inserting auniformly distributed compressive or pulling force directed along thecenterplane of said modules. The subject device of this invention avoidsdamage to the modules as a result of accidental mishandling wheninserting or withdrawing them, thereby endowing them with greatreliability notwithstanding the numerous manipulations to which they aresubjected.

A portable device according to this invention is characterized by thefact that it comprises:

a grip consisting of two elements movable relatively to each other andnormally kept spaced from each other by return springs;

two sets of movable arms pivotally mounted at either end of one of thegrip elements and capable, in their resting positions, of penetratinginto the rack on either side of the-module to be plugged in, which armscomprise claws adapted to engage into recesses provided for the purposein the lateral walls of the rack;

two actuating systems of the cam type which, when the operator moves thetwo grip elements toward each other, is effective in initially fetchingthe movable arms into a position wherein their claws engage into theanchoring recesses, and thereafter in exerting a pressure uniformlydistributed over the upper edge of the module whereby to cause the sameto engage into the bottom groove;

two extraction hooks fixed to either end of the second grip element andwhich, after the operator has turned the grip the other way round,enable him to engage them into holes provided for the purpose in themodule to be unplugged and to thereafter withdraw the same by moving thetwo grip elements toward each other, during which operation the gripreacts against the edges of the rack through two abutments fast with thegrip element provided with the claw-bearing movable arms.

The description which follows with reference to the accompanyingnon-limitative exemplary drawings will give a clear understanding of howthe invention can be carried into practice. i

In the drawings:

FIG. 1 is a perspective showing of a device according to this invention,portrayed in the position in which it must be grasped in order to plug amodule into a rack;

FIG. 2 is an end view of FIG. 1;

FIG. 3 is a side elevation view with partial cutaway;

FIG. 4 is a detail view on an enlarged scale showing the fastening clawactuating mechanism of the device in sectional side elevation;

FIG. 5 is a cross-section along the line V--V of FIG.

FIG. 6 is an explanatory illustration of the manner of operation of thedevice, as used for plugging a module into a rack;

FIG. 7 is a cross-section taken along the line VII- VII of FIG. 6;

FIG. 8 is an explanatory illustration of the manner of operation of thedevice, as used for withdrawing a module from a rack; and FIG. 9 is across-section taken along the line IX-IX of FIG. 8.

The device shown for exemplary purposes in the drawings may be likenedin general shape to a springtype dumb-bell in that it is formed by atwo-part grip, namely of two parallel cylinders 1 1,, which can begripped in one hand and tightened together against countering springs2,, 2,,. These springs are carried on two end posts 3,, 3,, whichlikewise form guides for the motion of element 1,, relatively to element1,. The posts 3,, 3,, accordingly have one of their ends fixed into thecorresponding ends of element 1,, as is clearly shown at 4 in FIG. 3,while the other element 1,, is provided with bushes 5 through which theassociated posts slide. The latter protrude through element 1,, andtheir outer ends are fitted with caps 6,, 6,, the functions of whichwill be explained in greater detail hereinafter. Adjacent its ends,movable element 1,, is provided with rods 7,, 7,, whose respective axesXX and YY lie in the vertical symmetry plane PP of the device, whichplane is shown in a dot-dash line in FIG. 2. The rods 7,, 7,, havetapering terminal portions 8,, 8,, which are curved to form extractionhooks 9,, 9,. It is important to note, as is clearly shown in FIGS. 1and 9, that the tapering portions 8,, 8,, are curved in such manner asto cause the pulling force exerted by the hooks to lie in symmetry planePP,.

Adjacent to the ends of element 1,, are fixed the bases of cylindricalrods 10,, 10,, extending through element 1,, being guided therethroughby bushes such as the bush 11 shown in FIG. 3. The unrestrained ends ofrods 10,, 10,,, which protrude from element 1,, respectively comprise,from top to bottom in FIG. 3, downwardly tapering frusto-conicalportions 12,, 12,, cylindrical portions 13,, 13,, of smaller diameterthan cylindrical portion 10,, 10,,, and transverse thrust plates 14,,14,, to the functions of which further reference will be made when themanner of operation of the device is described. The two ends of element1, comprise heads 15,, 15,, of rectangular shape for example and largerin size than the middle cylindrical portion 1,, whereby to accommodatetherein the upper portion of the anchoring claw assembly which will nowbe described with particular reference to FIG. 3 and to the two detailFIGS. 4 and 5.

Each head 15,, 15,, comprises two lateral slots 16,, 17, (or 16,,, 17which extend right through it. Accommodated in these slots and capableof swinging motion are the upper ends 18,, 19, of arms 20,, 21, and 20,,21 fulcrumed on pivots 22 23,. Springs 24 positioned respectively insaid slots continuously urge the pivotal arms 20,, 21,, 21 B toward theprotruding portion of the associated rods 10,, 10,, whereby to causethem to bear against the respective thrust plates 14,, 14,,. The lowerends of arms 20,, 21,, 20 21,, are provided with outwardly turnedfastening claws 24,, 25,, 24,, 25,, to which further reference will bemade when the manner of operation of the device is described.

Between the lateral arms 20, and 21, is disposed a transverse cammingplate 26 provided with two arms 27,, 28, engaged into said slots 16,,17, and capable of swinging motion therein about the pivots 22,, 23,.Adjacent its upper central portion, plate 26 is provided with acylindrical rivet 27 the head of which normally registers in contactwith the joint between frusto-conical portion 12, and thesmaller-diameter cylindrical portion 13, of guide 10,. Further, fixed toplate 26, beneath rivet 27, is a transverse spring blade 28 the ends ofwhich engage in corresponding recesses 29,, 30, formed in claw-arms 20,,21, (see FIGS. 4 and 5). Spring blade 28 is secured by a screw 31 and anappropriately arcuate second spring blade 32.

It will already be manifest that, through the agency of spring blades 28and 32, any pivotal motion of plate 26 about its hinge axis will causethe claw-arms 20,, 21, to pivot in the same direction against thecountering return springs 24, and that, if for any reason one of theclaw-arms should butt against an obstacle preventing it from pivoting,the three other claw-arms of the device are themselves nevertheless ableto pivot.

Particular reference will now be had to FIGS. 4, 5, 6 and 7 for adescription of the device in its function of ensuring perfect insertionof a module into a rack.

In FIGS. 6 and 7 a rack generally designated by reference numeral 33 isschematically illustrated in cross-section and longitudinal sectionrespectively.

Along the side walls 33,, 33,, of rack 33 are provided unifomtly spacedvertical slideways 34, 34, 34, 34, 34, 34 while in the rack bottom 33,-are formed transverse grooves 35,,, 35, 35, which interconnect theseslideways in pairs.

Further, formed in side walls 33, and 33,, are two horizontal grooves36,, 36,, for receiving the claws of the movable arms of the device andfor providing fastening points therefor, as will be explained in greaterdetail hereinbelow.

Each combination of two vertical slideways and the associated bottomgroove can receive a board or module equipped with its printed circuit,such as 37,,, 37, 37,,

Obviously, constant spacing between consecutive modules is so determinedthat, once the modules are in position, their printed circuits shouldconnect with one another and also so that it be possible for a claw-armto penetrate therebetween to a sufficient distance for its claw toregister with the corresponding fastening groove.

When a new module such as module 37,, is to be inserted, it is firstinserted manually into the vertical slideways reserved for the purpose(in this case the slideway 34, 34,,,). Module 37,, will then be in theposition shown in solid lines in FIGS. 6 and 7. At this stage recourseis had to the subject device of this invention for the final delicateoperation of plugging in the module, that is to say of inserting it intothe bottom groove 35 To that end the device is grasped in one hand andfetched into the position shown in solid lines in FIG. 6. This isaccomplished by inserting movable arms 20,, 20,, and 21,, 21,, betweenmodules 37, 37,, and 37,;,, 37,, respectively, until the lower edges ofcamming plates 26 bear against the upper edge of the module 37,, to beplugged in, the centerplane of which will then lie in the centerplane PPof the device.

Upper element 1,, is then pressed toward element 1,. During the initialstage of the descent of rods 10,, 10 it will be seen that frusto-conicalportions 12,, 12,, will coact with the rivet heads 27 to thrust thecorresponding plates 26 outwardly. Through the agency of spring blades28 and 32, the plates 26 accordingly thrust arms 20,, 21 and 20,,, 21,,outwardly, thereby causing the claws 24,, 25, and 24 25,, to engage inthe corresponding horizontal grooves 36,, 36,, which accordingly serveas fastening points. As element 1,, continues to be squeezed towardelement 1, against countering springs 2, and 2 thrust blades 14, and14,, on rods 10, and 10,, then exert, against the upper edge of module37, a symmetrical downward thrust since the device is locked in positionby the claws engaged in the horizontal grooves. Responsivelyto hisuniformly distributed and vertically centered force, module 37,1 isplugged into the lower groove 35A being uniformly nested therein inparallelism with the centerplane of the module. The various componentparts of the device are then in the final configuration shown in dottedlines in FIG. 6.

Once the module has been plugged in, the pressure on element 1 can bereleased to allow the latter to be raised by the return springs 2 and 2and the frustoconical portions 12,, 12,, of rods 10,, and 10,, toretract. The four claws 24 25 and 24 25 then revert to their initialresting positions and the device can be withdrawn from the rack.

As indicated precedingly, it should be noted that by vi'rtue of theelastic actuation of the claw-arms, it is possible for one of these armsto remain retracted while the others move into their fastening positionsif, for instance, that arm were to be hindered in its movement towardthe fastening groove by possibly bulky and projecting components likepotentiometers, capacitors, resistors, transistors, and the like,carried on certain modules. In that event the claw-arm in question willremain retracted without preventing plugging in from being effected bymeans of the other three claw-arms.

The device will now be described in connection with its use forwithdrawing a module from a rack, with particular reference to FIGS. 8and 9.

In order to avoid an unnecessarily lengthy description, the descriptionof the arrangement of the modules in rack 33 will not be repeated, andit should merely be noted that in this case all the modules 33, 33, 33

. are fully inserted into the corresponding bottom grooves 35 35, 35

In order to unplug one of the modules, for example module 37 the deviceis grasped in one hand, but this time the other way round, that is tosay with element 1,, upwards. The two ends 9 and 9,, of extraction hooks8,, and 8,, are then inserted into extraction holes 38 38 provided forthe purpose along the edge of each module.

The two elements 1 and 1 of the device are then squeezed together, andthe initial effect of this is to cause the two caps 6 6 to contact theupper face of the side walls 33,, and 33,, of the rack, which wallsaccordingly serve as reaction points for the device. If the two elements1 and 1,, continue to be squeezed together, lower element 1 will movetoward upper element 1 thereby causing module 37 to be withdrawn frombottom groove 35, and to be fetched into the position shown in dottedlines in FIG. 8. As explained precedingly, by virtue of the curved shapeof extraction hooks 8,, 8 module 37, is withdrawn along the centerplanePP, of the device and consequently along the centerplane of the module.After the latter has been extracted from bottom groove 35, it can easilybe removed from lateral slideways 34, 34, and then detached from hookends 9 and 9 An alternative module corresponding to the new programrequired can then be plugged in, in the manner described hereinabovewith reference to FIGS. 6 and 7.

It goes without saying that many changes and substitutions may be madein the embodiment described for exemplary purposes hereinbefore, withoutdeparting from the scope of the invention as set forth in the appendedclaims.

I claim:

1. A portable device permitting, as desired, either selective pluggingin of a printed-circuit module into one of a plurality of bottom groovesformed in a rack and above which groove the module is restrained bylateral slideways, or selective unplugging of one of the modules pluggedinto the bottom rack grooves, said device comprising: i

a grip formed by two elements movable relatively to each other andnormally held in mutually spaced relationship by return springs;

two sets of movable arms pivotally mounted at either end of one of thegrip elements;

said movable arms being capable, in their resting position, ofpenetrating into the rack and being provided with claws capable ofengaging into lateral recesses provided for the purpose in the sidewalls of the rack;

two cam type actuating means so devised that when the operator moves thetwo grip elements toward each other they initially cause said movablearms to move into a position wherein their claws engage in said lateralrecesses, and thereafter exert a pressure uniformly distributed over theupper edge of said module to be plugged in whereby to plug the same intothe bottom groove;

and two extraction hooks fixed to either end of the other grip element;

said hooks being so devised as to enable the opera tor, after he hasturned the grip the other way round, to engage them into holes providedfor the purpose in the module to be extracted and to thereafter unplugthe same by squeezing the two grip elements together, said grip thenreacting against the edges of the rack through the medium of twoabutment members fast with that grip element which supports said movableclaw-arms.

2. A device for plugging in and unplugging printedcircuit modules, asclaimed in claim 1, wherein the movable claw-arms of each set thereofare independent of each other in that they are urged toward theirrespective resting positions by individual return springs and towardtheir fastening positions through the agency of a common transversespring blade rigid with a central member which is hingedly mounted on apivot common to the movable claw-arms and which is itself subjected tothe direct action of the corresponding cam type actuating means.

, 3. A device for plugging in and unplugging printedcircuit modules, asclaimed in claim 2, wherein each cam type actuating means is formed by arod of which one end is fixed to that grip element which carries the twoextraction hooks, said rod extending through the other grip element andhaving, protruding therefrom, firstly a frusto-conical camming portionwhich coacts with an abutment fast with the central member hingedlymounted between the movable claw-anns, and secondly a cylindricalportion provided on its free end with a thrust plate which, when theoperator squeezes the two grip elements together, bears against theupper edge of the module to be plugged in.

4. A device for plugging in and unplugging printedcircuit modules, asclaimed in claim 1, wherein the hooks on the extraction members areoffset in such manner that the pull exerted by said extraction membersbe directed along the then coplanar centerplanes of the module to beunplugged and of the device itself, 7

supported on either end (if the grip, said posts having one of theirends fixed to that grip element which carries the movable claw-arms,extending through the other grip element the motion of which they serveto guide, and being extended by cap-forming members designed to reactagainst the rack when the operator uses the device for unplugging amodule.

1. A portable device permitting, as desired, either selective pluggingin of a printed-circuit module into one of a plurality of bottom groovesformed in a rack and above which groove the module is restrained bylateral slideways, or selective unplugging of one of the modules pluggedinto the bottom rack grooves, said device comprising: a grip formed bytwo elements movable relatively to each other and normally held inmutually spaced relationship by return springs; two sets of movable armspivotally mounted at either end of one of the grip elements; saidmovable arms being capable, in their resting position, of penetratinginto the rack and being provided with claws capable of engaging intolateral recesses provided for the purpose in the side walls of the rack;two cam type actuating means so devised that when the operator moves thetwo grip elements toward each other they initially cause said movablearms to move into a position wherein their claws engage in said lateralrecesses, and thereafter exert a pressure uniformly distributed over theupper edge of said module to be plugged in whereby to plug the same intothe bottom groove; and two extraction hooks fixed to either end of theother grip element; said hooks being so devised as to enable theoperator, after he has turned the grip the other way round, to engagethem into holes provided for the purpose in the module to be extractedand to thereafter unplug the same by squeezing the two grip elementstogether, said grip then reacting against the edges of the rack throughthe medium of two abutment members fast with that grip element whichsupports said movable claw-arms.
 2. A device for plugging in andunplugging printed-circuit modules, as claimed in claim 1, wherein themovable claw-arms of each set thereof are independent of each other inthat they are urged toward their respective resting positions byindividual return springs and toward their fastening positions throughthe agency of a common transverse spring blade rigid with a centralmember which is hingedly mounted on a pivot common to the movableclaw-arms and which is itself subjected to the direct action of thecorresponding cam type actuating means.
 3. A device for plugging in andunplugging printed-circuit modules, as claimed in claim 2, wherein eachcam type actuating means is formed by a rod of which one end is fixed tothat grip element which carries the two extraction hooks, said rodextending through the other grip element and having, protrudingtherefrom, firstly a frusto-conical camming portion which coacts with anabutment fast with the central member hingedly mounted between themovable claw-arms, and secondly a cylindrical portion provided on itsfree end with a thrust plate which, when the operator squeezes the twogrip elements together, bears against the upper edge of the module to beplugged in.
 4. A device for plugging in and unplugging printed-circuitmodules, as claimed in claim 1, wherein the hooks on the extractionmembers are offset in such manner that the pull exerted by saidextraction members be directed along the then coplanar centerplanes ofthe module to be unplugged and of the device itself, respectively.
 5. Adevice for plugging in and unplugging printed-circuit modules, asclaimed in claim 1, wherein the return springs which urge the two gripelements away from each other are coil springs which surround postssupported on either end of the grip, said posts having one of their endsfixed to that grip element which carries the movable claw-arms,extending through the other grip element the motion of which they serveto guide, and being extended by cap-forming members designed to reactagainst the rack when the operator uses the device for unplugging amodule.